Lubricating oil compositions



Patented July 10, 1 945 2,380,205 LUBRICATIN G OIL COMPOSITIONS Paul R. Van Ess, Berkeley,

and Ellis R. White,

Albany, CaliL, assignors to Shell Development Company, San Francisco,

of Delaware CaliL, a corporation No Drawing. Application March 16, 1942, Serial No. 434,892

21 Claims.

This application is acontinuation-in-part of our copending application Serial No. 424,545, filed December 26, 1941, and of application Serial No. 376,330, filed January 28, 1941,

This invention relates to compounded lubricating oils and greases containing added ingredients which improve their properties in one or more important respects. It also deals with the addition of oil-soluble addition agents to compounded mineral oils to produce lubricating oils of improved anti-wear properties for internal combustion engines. More particularly, it deals with the addition to lubricating oils of certain oil-soluble alicarbocyclic compounds, which compounds have the property of modifying or reducing the hardness of carbon formed on pistons and of preventing the baking of carbon in piston grooves to the point of hardness and thus not only retarding the sticking of piston rings when running internal combustion engines for long periods of time, but also preventing the scratchin of pistons caused by hard carbon.

It is known that in modern internal combustion engines, such as aviation gasoline engines, due to their high-power output and their relatively high temperatures, or high speed Diesel engines,

due to incomplete combustion of the fuel, piston rings have a tendency to become stuck in the grooves due to baked carbon, and the pistons tend to become worn. Baked carbon on pistons lubricated with hydrocarbon oils, in general, may be said to increase in hardness and decrease in adhesiveness with rise in viscosity index of the oil.

We have discovered that certain oil-soluble saturated alicarbocyclic alcohols or their esters are useful in modifyinghard carbon; and that highly refined lubricating oils which contain small amounts of such compounds are remarkably stable and have the valuable property of'positively retarding ringsticking, and overcoming and preventing piston scuifing and scratching usually associated with the severe service conditions such as are encountered in Diesel engines and the like.

In stating that the cyclic alcohols or esters modify the carbon formation on the piston, we

mean that instead of the usual hard, tough, adhesive carbon deposits, 2. soft, velvety, nonadherent carbon deposit is formed in the presence of the cyclic alcohols or their esters which deposit is almost oily in character. It is so non-adherent that it may be removed by wiping with a soft cloth, leaving a clean metal surface. N o explanation can be offered for the above-observed phenomenon.

The cyclic alcohols, or their esters of monocarboxylic acids possessing carbon-modifying properties may be represented by the general formula wherein R represents a high-molecular weight saturated hydrocarbon radical having at least 12 carbon atoms and containing at least one alicarbocyclic ring, X represents a hydroxy or ester radical attached to a nuclear carbon of said ali carbocyclic ring, and n is an integer, preferably having the value 1.

Esters of poly-basic acids may contain as many R radicals as there are hydrogen ion-forming radicals, in which case all of the latter are esterified and the ester is neutral and non-ionizing.

Saturated alicyclic alcohols of at least 12 carbonatoms useful for our purpose may be mononuclear m'onohydroxy alcohols of at least 12 carbon atoms, such as straight and branched chain alkyl cyclopentanols, e. g., tri-n-propyl, triisopropyl, di-primary, secondary or tertiary .butyl, dimethyl amyl, methyl hexyl, ethyl hexyl, dimethyl hexyl, heptyl, methyl heptyl, diheptyl, octyl, isooctyl, etc., cyclopentanols; normal and branched alkyl cyclohexanol, e. g., (ii-isopropyl cyclohexanol, di-n-amyl cyclohexanol, di-secondary-amyl cyclohexanol, di-tertiary amyl cyclohexanol, n-hexyl cyclohexanol, di-n-hexyl cyclohexanol, di-tertiary-hexyl cyclohexanol; or polyand branched alkyl decalols, e. g., di-methyl decalol, tri-methyl decalol, tetra-methyl decalol, etc., ethyl-methyl decalol, ethyl decalol, di-, tri-, tetra-ethyl decalols, corresponding propyl, butyl, amyl, etc., decalols; bi-alicyclic alcohols having branched alkyl radicals produced by hydrogenating the condensation product of mesityl oxide or isophorone, hydrogenated anthracene-ols and alkyl substituted hydrogenated anthracene-ols, e. g., methyl, ethyl, isopropyl, n-, sec-, tert-butyl hydrogenated anthrace'ne-ols, ethyl-isopropyl (saturatedl anthracene-ols, isobutyl-tert-amyl (saturated) anthracene-ols, etc.; alicyclicmononuclear polyhydroxy alcohols, such as alkyl and branchedalkyl cyclopentane diols, e. g., ethylamyl-cyclopentane-diols, isopropyl butyl-cyclopentane-diols, sec-butyl-tert-amyl cyclopentane dlols, di iso-amyl-cyclopentane-diols, corresponding cyclohexane-diols; alicycllc polynuclear polyhydroxy alcohols, such as alkyl and branched allwl deca and polyhydro (saturated) anthracene- .(under engine conditions) in (saturated) anthracene-diols.

Of the many groups of alcohols which are useful for our purpose, the following are preferred: (1) those having at least one and preferably alicyclic nuclei of six carbon atoms each; (2) those having at least one branched aliphatic radical attached to the alicyclic nucleus, preferably to a G-atom nucleus; (3) those being free from aryl radicals; (4) those containing a single hydroxy group. If desired the alcohols may contain certain polar substitution radicals which do not reduce their thermal stability, such as chlorine, sulfide, hydrosulfide, ether, etc., radicals.

The reason for the particular eiiectiveness of the described alcohols in the matter of softening normally hard carbon deposits is not definitely known at this time. However, it is known that in phanic, thiocarbonic, thiocarbamic, or thioallophanic, chlorinated or sulfurized fatty acids, etc.

two I order to be effective, the alcohols must possessv certain important properties which are: (1) They must have relatively high boiling temperatures so asto remain in the lubricating oil-in effective concentration even after prolonged use of the oil. (2) They must be thermally stable, i. e., they must not readily decompose or polymerize under engine conditions. Therefore, they must not contain 01efinic double bonds. In particular, they must be suflioiently stable even at the extremely high temperatures to which the toplands of pistons of internal combustion engines are exposed, so that the carbon deposited thereon remains soft. Extended experiments on the relative hardness of carbon deposits formed under various conditions have indicated that the hardness of the carbon depends primarily on the tuents retained by it. The presence of even small amounts of one or several of the described alcohols in a lubricating oil strangely enough results the formation of an oily, rather than a dry, carbon deposit, even though the oil in the absence of the alcohol may, under the same conditions and in the same engine, deposit a dry and hard carbon. (3) The alcohols must be oil-soluble. Most of the so-called' "higher saturated fatty alcohols of 12 and more carbon atoms, such as lauryl, cetyl, st'earyl, etc., alcohols, are very little soluble in hydrocarbon oils. They are solids at normal room temperatures, some of them being waxy, others crystalline. In contrast, the lower" of our alicyclic alcohols described, i. e., those having between about 12 to 30 carbon atoms, are oily normal room temperature, while the higher ones are glassy, non-crystalline solids. They are much more soluble in hydrocarbon oils than the fatty alcohols of the same numbers of carbon atoms, and also are much better softeners for the transformation of hard carbon to soft carbon.

Acids suitable to form the esters of the above alcohols are primary, monoor polycarboxylic acids and include fatty acids, both lower and higher, naphthenic acids, wool fat acids, paraflin acids, aromatic carboxylic acids as benzoic, naphthoic, alkyl benzoic or naphthoic, phenyl acetic,

' phenyl stearic, hydrogenated rosin, carbonic, oxalic, succinic, alkyl succinic, sebacic, agaric, etc.,

hydroxy oramino phenyl stearic, carbamic, allocontent of oily consti-' viscous liquids at Useful esters may also be derived from certain inorganic acids such as phosphorous acid, phosphoric acid, mono, di, tri, and tetra thio-ortho, meta, pyro and hypophosphoric acids, arsenous acid, sulfuric acids and the organic radical substituted thio and oxy acids of the above, such as phosphonic, hydroxy phosphonic, phosphinic, sulfonic acids, etc.

Of the above-mentioned alcohols, a preferred class having from 16 to 30 carbon atoms may be produced by condensing lower aliphatic ketones such as acetone, methyl ethyl ketone, etc., to products of the type of isophorone or mesityl oxide, further condensing the latter to form bieyclic unsaturated ketones and then hydrogenating the latter to the corresponding alcohol. Also very desirable are the closely related alkylated decalols which maybeprepared by hydrogenation of alkyl naphthols.

Preferred esters are amino carbonates, e. g., the carbamates, allophanates, imido carbonates, hydrazine carbonates, etc., of the preferred alcohols, because in addition to carbon modifying properties, these particular esters possess pronounced anti-wear properties. Other desirable esters are the fatty acid esters of thio-phosphorus acid.

Amounts of cyclic alcohols or their compounds to be added to lubricating oils effectively to modify and reduce the hardness of carbon deposits formed on pistons need not be large. In general, the amounts required vary from about .1 %-10%, and preferably from .5%-5%, depending on conditions to be met. These amounts are usually sufficient to take advantage of other useful properties. which the compounds may have such as anti-.

wear, anti-ringsticking, etc.

Methods of manufacture of the cyclic alcohols comprise the above-mentioned condensation of lower aliphatic ketones to cyclic ketones and hydrogenation to the corresponding alcohols; hydrogenation of alkyl naphthols, anthraquinone, etc., to the alcohols; chlorination and subsequent hydrolysis of chlorination products of cycle paraflins having at least 12 carbon atoms; Grignard reaction applied to open long chain ketones, etc.

The desirable properties of our lubricating oils, containing saturated alicarbocyclic alcohols or their esters may be further improved, if desired, by use in combination with certain anti-oxidants, detergents, corrosion inhibitors, extreme pressure compounds, soap thickeners to produce grease. etc. If desired, mixtures of different alcohols of this invention and/or their esters may be used to advantage.

Example I An S. A. E. lubricating oil,-having.a viscosity I index of 55, containing 2.25% calcium petroleum sulfonate (produced by converting a commercial mahogany soap to the calcium salt), 0.25% phenyl alpha-naphthylamine and 1.0% C18 cyclo-alkyi alcohol was subjected to a 126-hour test in a Caterpillar test engine operated at 850 R. P. M.,and at 16.7 B. H. P. At the end of the run the piston rings were free, the piston was clean, and the topland of the piston was free of hard carbon. The metal was not scuffed. What small amount of carbon had deposited at the bottom of the top ring groove was soft and easily removed.

Example II A lubricating oil of s. a E. 30 containing 1% of a Cu cyclic alcohol was subjected to a 20-hour Scar diameter of these compounds.

test in a single cylinder Lauson engine operating at 1700 R. P. M. under conditions known to produce hard carbon, lacquerin mineral lubricating oils. At the end of the run, the piston as it came from the cylinder had a thin coating .of soft, velvety carbon which could be rubbed .011 with a soft cloth, leaving a clean piston having no stuck rings and substantially no topland scratching.

Example III A sample of western lubricating oil, S, A. E. 20 grade, was divided into two portions. 1% by weight of a bi-alicyclic C18 allophanate prepared by the reactio cohol prepared by condensation of acetone and hydrogenation of the condensation product was dissolved in one portion. Both the blended and unblended portions were tested in the Four-Ball n of carbamyl chloride with the alg, etc., with straight Example V A sample of western lubricating oil, S. A. E. 30 grade, was divided into portions A, B, and C. Portion A was not blended. To portion B was added 1% by weight of tri-cresyl phosphate. To portion was added 1% by weight of C18 cycloalkyl thiophosphate prepared as follows: C18 bialicyclic alcohol was reacted .with phosphorus pentasulfide in a 2:1 mol ratio at 150 C. for 46 hours. The reaction product was dissolved 'in benzene, the solution filtered and the benzene distilled off by warming on the steam bath under reduced pressure. The benzene soluble residue was a clear, brown, viscous liquid ready to be added to the lubricating oil.

The blended and unblen subjected to a 53 gine operated at -'hour test in a C. F. R. Diesel en- 900 R. P. M. and at 2 /2 B. H. P.

Machine described in Engineering, vol. 136, July to determine performance properties. Results of 14, 1933. This apparatus comprises a set of four the tests were as follows:

Table I Piston Cu-Pb bearggi Additi n agent gii g Carbon ing corrosion gins. mg./sq. cm.

Skirt-hard, adhesive lacquer. A None .130 Deposit-medium heavy.-.

Rings-none stuck, but dirt Skirt-b1ack, adhesive lacquer.

B Tri-cresylphosphate 145 Deposit-heavy, medium hard l. 22

' gk i i bi 1}1 "a id? u-t-c can, on y ac acquer aroun re case.. 0 c g thiophos 125 {Deposit-about )6 as much as A and medium soft.-. .031

p e Rings-free, clean steel balls arranged in pyramid formation. The top ball is rotated by spindles against the three Unblended Blended I oil oil.

The oil improving agents contemplated by this invention may be single compounds or mixtures Example IV A sample of western lubricating oil, S. A. E. grade, containing 1% by weight of C18 bi-alicyclic allophanate, prepared by the reaction of carbamyl chloride with the alcohol prepared by condensation of acetone and hydrogenation of the condensation product was subjected to four 20-hour periods of test in a C. F. R. Diesel engine operating under severe conditions, at a maximum 0. m. e. p. for the engine at a load of 2 /2 H. P. and at a speed of 900 R. P. M. At the end of each 20- hour period, the piston was removed from the cylinder and examined. The carbon and lacquer deposits on the piston crown, topland, ring grooves and on the skirt were unusually soft and could be rubbed off easily. The base oil alone, when so tested, yielded a medium hard deposit of carbon and lacquer that would not rub off easily. There was also obtained 24% less wear tive oil than with the base oil.

vlower balls which are clamped in a stationary with the addithereof, having at least 12 carbon atoms in the alicyclic radical.

2. The lubricant of claim 1, wherein the cyclic radical has at least one branched alkyl radical attached to the nucleus.

3. The lubricant of claim 1, wherein the cyclic radical is bicyclic.

4. The lubricant of claim 1, wherein the alleyclic radical contains at least one fi-carbon atom ring. 1 5. An'improved lubricant comprising a mineral lubricating oil having dissolved therein .1% to 10% ofan oil-soluble compound selected from the group consisting of saturated polynuclear monohydroxy alicarbocyclic alcohols and esters thereof, having at least 12 carbon atoms in the alicyclic radical. v i

6. An improved lubricant comprising a mineral lubricating oil having dissolved therein .5% to 5% of an oil-soluble compound selected from the group consisting of saturated polynuclear mono hydroxy alicyclic alcohols and esters thereof, having at least 12 carbon atoms in the alicyclic radical.

7. The lubricant of'claim 1, wherein the alcohol is a hydrogenated condensation product of a compound selected from the group consisting of mesityl oxide and isophorone.

8. An improved lubricant comprising a mineral lubricating oil having dissolved therein an amount of an oil-soluble saturated polynuclear monohy- -droxy alicarbocyclic alcohol having at least 12 carbon atoms in the alicyclic radical said amount ded portions were each being sufllcient to soften carbon deposits in internal combustion engines.

9. An improved lubricant comprising a mineral lubricating oil having dissolved therein .1% to I attached to the nucleus.

11. The lubricant of claim 8, wherein the alicyclic radical contains at least one 6-carbon atom rin 12. The lubricant of claim 8, wherein the cyclic radical is bicyclic.

13. The lubricant of claim 8, wherein the alcohol-is a decalol.

14. An improved lubricant comprising a mineral lubricating oil having dissolved therein an amount of an oil soluble saturated monohydroxy bi-alicarbocyclic alcohol having at least 12 carbon atoms in the alic'yclic radical sufficient to soften carbon deposits in internal combustion engines,

wherein said alcohol is a hydrogenated condensation product of a compound selected from the group consisting of mesityl oxide and isophorone.

15. An improved lubricant comprising a mineral lubricating oil having dissolved therein .5% to 5% of an oil soluble saturated polynuclear monohydroxy alicarbocyclic alcohol having at least 12 carbon atoms in the alicyclic radical.

16. The lubricant of claim 14, wherein the alcohol is derived from a lower aliphatic ketone condensation product.

17. The lubricant of claim 14, wherein the alcohol is a hydrogenated condensation product of mesityl oxide.

18. The lubricant of claim 14, wherein the alcohol is a hydrogenated condensation product of isophorone.

19. A compounded lubricating oil containing a beneficial amount of an oil-soluble, ester of a. saturated, polynuclear, monohydroxy alcohol, said alcohol having a minimum of 12 carbon atoms and said hydroxy radical being directly attached to a nuclear carbon atom.

20. The composition of claim 29 wherein the alcohol is a hydrogenated condensation product of an aliphatic ketone.

21. The composition of claim 29 wherein the -alcohol is a hydrogenated 01a carbocyclic condensation product of an aliphatic ketone.

PAUL R. VAN ESS. ELLIS R. WHITE.

Certificate of Correction Patent No. 2,380,205. July 10, 1945.

PAUL R. VAN ESS ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 4, second column, lines 20 and 23, for the claim reference numeral 29 read 19 and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent'Ofiice.

Signed and sealed this 24th day of September, A. D. 1946.

LESLIE FRAZER,

First Assistant Commissioner of Patents. 

